Gravity responsive switch



y 1965 J. R. MILLER 3,183,321

GRAVITY RESPONSIVE SWITCH Filed July 8, 1960 2 Sheets-Sheet 1 l4 2 so l6 z H6. 4 H612 F/6.3

INVENTOR. JAMES R. MILLER F/.6 ra/g, 121

May 11, 1965 J. R. MILLER GRAVITY RESPONSIVE SWITCH 2 Sheets-Sheet 2 Filed July 8, 1960 PITCH YAW .II/lll rlllilirf .lflflfl 'II/CVA INVENTOR. JAMES A. MILLER ATTOlZ/VEY United States Patent 3,183,321 GRAVITY RESPONSIVE SWITCH James R. Miller, Huntington, N.Y., assignor to Aerodyne Controls Corporation, Farmingdale, N.Y., a corporation of New York Filed July 8, 1960, Ser. No. 41,541 11 Claims. (Cl. ZOO-61.48)

This invention relates to switches responsive to the force of gravity or multiples thereof.

-Among its many uses it is particularly adaptable to aviation where the maneuverability of airframes, including airplanes and missiles, results in loads and forces exceeding the normal acceleration of gravity which is denoted G. These movements of airframes, particularly sudden movements, develop forces or loads exceeding one G and sometimes equalling or exceeding many Gs. These destructive forces, of course, when excessive, can cause damage to or the disintegration of any aero-vehicle.

-The present switch responds to the G forces or loadings to make or close an electric circuit thereby to control'the fuel supply of the vehicle, the operating of instruments or meter, or the firing of an explosive charge.

Essentially the present switch proposes to close or make an electrical circuit in response to gravity forces or loading for any purpose or reason.

With the above and other objects in view, as will be apparent, this invention consists in the construction, combination and arrangement of parts all as hereinafter more fully described, claimed and illustrated in the accompanying drawings wherein:

FIG. 1 is an external perspective view of a switch made according to the present invention;

FIG. 2 is a longitudinal section through the switch, being taken generally along line 2-2 of FIG. 3;

FIG. 3 is an elevation of the terminal end of the switch being taken from the right of FIG. 2;

FIG. 4 is an elevation of the end of the switch opposite to that shown in FIG. 3;

FIG. 5 is an outside elevation of the insulating disc or end partition carrying an apertured contact plate;

FIGS. 6, 7 and 8 are inside elevations of the insulating disc or partition each illustrating a differently apertured contact plate;

FIG. 9 illustrates a specimen vector diagram; and

FIG. 10 is a sectional view similar to FIG. 2 showing a slightly modified form of the instant invention.

The switch herein contemplated is sensitive or responsive to the force of gravity and multiples thereof and is susceptible of many uses and adaptations under conditions developing abnormal gravity loadings or G5, whereupon the switch is operated to perform some function. For example, in the operation of air to air missiles or rockets it is essential that the rocket or missile be maintained on apredetermined course or intended variations of such course.

However such rocket or missile may malfunction making sudden turns and deviations from its set course. This is dangerous to aircraft in the vicinity and especially to the launching vehicle. In making such turns and sudden maneuvers the rocket or missile develops G loadings that would automatically operate the present switch and close a circuit cutting off the power supply of the missile or even destroying the missile. Another use can be on vehicles testing the surface of a highway or the actual loads resulting from vibrations caused by the highway. Here the gravity switch is mounted on a vehicle so that it responds to vibrations caused by irregularities on the road surface. The switch in this example makes or closes a circuit which can control operation of a counter and thereby record the number of irregularities encountered on the road surface. By associating the counter circuit with a machine for drawing graphs the switch can develop a chart indicating the severity of the irregularities encountered.

The foregoing are two examples of uses of the present invention and many others can be given or developed. It is understood that the mechanisms, systems and instruments controlled by the present switch form no part of the present invention and therefore are not to be construed as limitations thereof. The present invention is a switch will make or close an electrical circuit in response to gravity or G forces without regard to purpose or function of said circuit. In carrying out the present invention a hollow tubular casing 10 is provided to house the switch and its components. At one end this casing 10 is provided with a relatively substantial or thick bottom 11 having a central aperture 12 flanked by a pair of internally threaded mounting holes 13. These mounting holes do not pierce the bottom 11 of the casing and therefore have no communication with the interior thereof. A filling opening 14 pierces the bottom 11 and communicates with the interior of the casing 19 at its inner end. This filling opening tapers inwardly from the outer surface of the bottom 11 and is intended to receive a tapered sealing pin 15, somewhat shorter than the length of the filling opening 14. When the tapered pin 15 is firmly driven into opening 14 the latter is completely closed and sealed. As will be seen herein access to the interior of the casing 10 is ultimately closed and it is substantially hermetically sealed.

In the central aperture 12 of the bottom 11 is mounted a metallic bushing 16 which surrounds the adjacent extremity of a cantilever beam or rod 17. This bushing tightly engages the extreme end portion of the rod or beam 17 and is seated securely in the aperture 12 in the bottom 11 to seal said aperture, mount the rod 17 at one of its ends and electrically connect it to the casing 10. This beam or rod 17 extends centrally through the casing 10 from the bottom 11 to terminate near the end of the casing opposed to such bottom 11 which end is initially open and unobstructed.

The open end of the casing 10 is provided with internal shoulder 18. A partition or disc 19 of any suitable insulating material rests snugly on the shoulder 18 and is so disposed that its outer surface is spaced inwardly from the lip 10 defining the open end of the casing. This disc 19 is fabricated from any suitable or adaptable electrical insulating material and is provided with a central opening 24). Counter-sunk in the inner face of the disc 19 is a metal contact plate 21 having an aperture 22 aligned axially of the casing 10 with the opening 20 in the disc 19. The aperture 22 of the contact plate 21 is shaped to reproduce the vector diagram created by the operation of the present switch in response to gravity loading and this aperture therefore may be any required shape.

The contact plate 21 is secured to the inner surface of the insulating disc 19 by a series of eyelet rivets 23 which extend completely through the plate 21 and the disc 19 but with their extremities disposed below and separated from the planes of the surfaces of both the disc 19 and the contact plate 21. Thus these rivets do no project beyond the surface of the disc 19 on one side or the plate 21 on the opposite side of such disc. The plate 21, of course, is made of electrically conductive material.

The disc 19 together with the plate 21 is held against rotary movement within the casing by a pin or stake 24 imbedded in the shoulder 18 of the casing to project into a corresponding groove or hole 24 in the peripheral portion of the insulating disc 19 when seated on the shoulder.

Not only does the stake 24 counteract rotary movement of the disc 19 but it serves as a guide to properly position the disc with reference to other components of the switch.

The contact aperture 22 in the plate 21 is usually smaller than the central opening of the disc 19 and it is shaped to reproduce the desired vector diagram. In FIGS. 6, 7 and 8 .are respectively illustrated various contours for the aperture 22 such as square, round and oblong.

In addition to the openings in the disc 19 for the eyelet rivets 23, a relatively large terminal opening is provided through the disc 19. This opening 25 extends completely through the disc 19 to terminate directly over a spring finger 26 formed in contact plate 21 by the slot or slots 27.

A cover plate 28 coacts with the exposed surface of the disc 19 and this cover plate completely fills the open end of the casing 10 so that its periphery abuts snugly against the inner surface of the casing 10 and its inner surface rests flush against the outer surface of the disc 19 inwardly of the lip 10' at the open end of the casing 10. The cover plate 28 is pierced by a terminal which is insulated from the cover plate and at its inner end 31 projects into and through the terminal opening25 in the disc 19 to bear against the underlying spring finger 26 of the contact plate 21. A second terminal 29 is secured to and electrically connected with the cover plate 28 and through it to the casing 10. Both of the terminals 29 and 30 project outwardly from the plate 28 and are disposed adjacent and substantially parallel to each other.

To insure an electrical contact between cover plate 28 and the casing 16), and also to retain the plate 28, and disc 19 in place, the lip 10' of the casing defining the open end thereof extends beyond the outer surface of the plate 28. By welding or soldering the plate 28 to the projecting lip 10 of the casing 10, the plate is permanently and electrically secured to the casing and the joint between the cover plate and the casing is hermetically sealed thereby. When so disposed the inner surface of the cover plate 28 rests flush against the outer surface of the insulating disc or partition 19 with the inwardly projecting extremity 31 of the terminal 30 hearing firmly against the spring finger 26 of the contact plate 21.

Within the casing 10 and mounted upon the beam or rod 17 is a bob-weight 32 whichis disposed on said rod to adjoin the contact plate 21. This bob-weight 32 and its associated parts constitute a mass adjoining the extremity of the rod or beam 17 to deflect it relative to the bottom 11 in response to gravity or G forces. The bob-weight 32 may be rigidly and permanently secured to the rod or beam 17 or it may be mounted for adjustment on such beam or rod by the internally threaded passage 33 in the bob-Weight coacting with the threads 34 on said beam or rod; tool holes being provided for that purpose.

Attached concentrically to the bob-weight 32 is a projecting contact 35 forming a continuation of the rod or beam 17. The length of the contact 35 is sufficient to dispose its end portion within the contact aperture 22 of the plate 21. When the rod or beam 17 flexes and the bob-weight moves within the casing 10 in response to gravity the contact 35 will engage any edge of the plate 21 defining the opening 22 and projecting beyond the edge of the opening 20 in the disc 19, dependent on the direction of movement of the bob-weight. This closes or makes an electrical circuit from the terminal 30 and contact plate 21 through contact 35, the beam or rod 17, the casing 10, the cover plate 28 to the terminal 29, the wires of the circuit being attached to the terminals 29 and 30.

filling in the casing 10 with damping fluid is as follows:

First the switch, completely assembled as above de-' scribed, is submerged in a container filled with damping fluid.

Second: This container with one or more switches suba ting air are repeated several times to insure that no air is trapped within the casing 10.

Fourth: With the switch in the damping fluid and inverted to permit access to the tapered filling hole 14,

the switch and the damping fluid therein is heated to a predetermined temperature, viz., a temperature in excess of the highest expected service temperature, thereby causing the damping fluid to expand to completely fill the casing 10 and to bleed through filling opening 14.

Fifth: The switch is held at the temperature in excess of the highest expected service temperature for a period of time to establish a uniform heat distribution throughout.

Sixth: The tapered sealing pin 15 then is driven into the tapered filling opening 14 while the switch is held at the aforesaid temperature thereby sealing casing 10 while completely filled with damping fluid.

When the switch is allowed to cool the volume of the damping fluid will contract creating and establishing a void within casing but still approximately subm'erging the bob-weight 32 in the damping fluid.

- To regulate the mass and the damping constant of the bob-weight 32 an apron 36 may be formed thereon to surround the rod or beam 17 within the casing 10. This apron 36 controls the damping constant of the switch and the proportions of the apron 36 may be adjusted to the required damping constant. Of course the size of the bob-weight 32 and the provision and the degree of extension of the apron 36, like the shape and size of the contact aperture 22 of the plate 21 is determined by the required operating conditions, and the function and purpose of the switch. The damping affect of the fluid within the casing 10 prevents free and continuing vibration of the bobweight 32 and contact 35 that would result in repeated opening and closing of the circuit between terminals 29 and 30 and retains the contact 35 of the bob-weight 32 in a periodic engagement with the edge of the contact aperture 22 of the plate 21. Thus when such contact is established, it is maintained until the conditions displacing the bob-weight 32 and flexing its beam or rod 17 have ceased.

As the ambient temperature of the switch increases the viscosity of the damping fluid and the void within the casing 10 both decrease but as the ambient temperature of the switch decreases the viscosity of the damping fluid and the void within casing 10 both increase, thereby lowering pumping losses and compensating for increased viscosity of the damping fluid.

The shapes and sizes of the contact aperture in the plate 21 can be many and varied. Three have been shown, one square (FIG. 8), one round (FIG. 6), and one oblong (FIG. 7). In FIG. 7 it will be noted that the ends of the oblong opening 22 extend over the insulating disc 19 so that only the longitudinal edges of such opening can engage the contact 35 of the bob-weight 32. I

The switch shown in FIG. 10, in construction and operation, is substantially identical with that shown in other figures, the differences between the two switches residing in proportions. In FIG. 10 the barrel of the casing 10 is increased in the length and the contact 35 is correspondingly longer. By this arrangement the degree of'movement of the extremity of contact 35 is increased or multiplied.

What is claimed:

1. A gravity responsive switch comprising a hollow casing closed at one of its ends and open at the other, said closed end having several internally threaded mounting holes extending partially through it, a cantilever rod centrally and electrically secured to inner face of the closed end of said casing, an insulating disc mounted in the open end of the casing having a central contact opening and a terminal opening laterally disposed relative to the contact opening both of said openings passing completely through said disc, a contact plate secured to the inner face of the insulating disc and provided with an opening aligned with and smaller than the contact opening therein, a cover plate overlying the outer-face of the disc, peripherally connected electrically to the casing, a pair of terminals carried by the cover plate, one electrically connected to the plate and the other insulated from and passing through said plate to project through the terminal opening of the disc and bear against the contact plate, a bob-weight surrounding and attached to the cantilever rod, and a contact concentrically secured to the bobweight and projecting into the aligned contact openings, of the plate and disc aforesaid.

2. A gravity responsive switch comprising a hollow casing, a dielectric member disposed within and fixed to said casing adjoining one of its ends, a relatively thin, flat contact plate secured parallel to and flush against the inner face of said member being smaller in area than said member and having a central contact aperture, a pair of terminals for a normally open circuit located at that end of the casing containing the dielectric member and contact plate, one of said terminals being connected electrically to the casing and the other being insulated from the casing and electrically connected to the contact plate and contact means electrically connected to that end of the casing opposed to said contact plate and dielectric member and adapted to flex to bring its free extremity into and out of engagement with the edge of the contact aperture of the contact plate thereby to make and break said normally open circuit.

3. A gravity responsive switch comprising a hollow casing integrally closed at one and open at its opposite end, a dielectric member disposed in and fixed to the casing adjoining its open end; said member having a central opening, a contact plate parallel and aflixed to the inner surface of said member having a smaller area than the latter and a contact aperture in substantial registration with the central opening of the dielectric member, means for sealingly closing the open end of said casing, a spring rod carried by and electrically connected to the integrally closed end of the casing with its free passing through the aperture in the contact plate and projecting into the central opening of said member for engagement with the edge of the contact plate aperture as the rod flexes in response to gravity, the shape and size of the aperture in the contact plate determining the vector diagram of the switch, and damping means within the housing and associated with the gravity responsive rod.

4. A gravity responsive switch comprising a hollow casing fabricated of electrical conducting material closed by an integral wall at one of its ends and open at its opposite end, an insulating disc seated in the open end of the casing provided with a relatively large central opening, a contact plate of smaller diameter than the insulating disc permanently fixed to the inner face of said disc and having a central contact aperture therein, the unitary disc and plate coacting with the casing and its end wall to define a chamber, a cantilever rod fixed centrally to said end wall and extending concentrically through the chamber, a bob-weight mounted on and secured to said rod carrying a contact projecting through the contact aperture of said plate, a cover plate overlying the outer face of the disc closing and sealing the open end of the casing and having electrical contact with the casing, and a pair of terminals one attached to said cover plate and the other insulated from the cover plate and attached to the contact plate.

5. A gravity responsive switch comprising a hollow casing fabricated of electrical conducting material closed by an integral wall at one of its ends and open at its opposite end, an insulating disc seated firmly in the open end of the casing provided with a relatively large central opening, a contact plate of smaller diameter than the insulating disc counter-sunk in and permanently fixed to the inner face of said disc and having a central contact aperture therein smaller than the central opening in the disc, the unitary disc and plate coacting with the casing and its end wall to define a chamber, a cantilever rod fixed centrally to said end wall and extending concentrically through the chamber, a bob-weight mounted on and secured to said rod, carrying a contact projecting through the contact aperture of said plate, a cover plate overlying the outer face of the disc to close and seal the open end of the casing and having electrical contact with the casing, and sealable means whereby the chamber within the casing may be filled with damping fluid.

6. A gravity responsive switch comprising a hollow casing fabricated of electrical conducting material closed by an integral wall at one of its ends and open at its opposite end, an insulating disc seated firmly in the open end of the casing provided with a relatively large central opening, a contact plate of smaller diameter than the insulating disc countersunk in and permanently fixed to the inner face of said disc and having a central contact aperture therein smaller than the central opening in the disc, the unitary disc and plate coacting with the casing and its end wall to define a chamber, a cantilever rod fixed centrally to said end wall and extending concentrically through the chamber, a bob-weight mounted on and secured to said rod, including a contact projecting through the contact aperture of said plate, a cover plate overlying the outer face of the disc to close and seal the open end of the casing and having electrical contact with the casing, scalable means piecing the end wall of the casing for feeding damping fluid to the chamber within the casing, and a pair of terminals one attached to the cover plate and through it electrically connected to the casing and the other insulated from and passing through the cover plate to traverse the insulating disc and be connected to the contact plate carried thereby.

7. A gravity responsive switch comprising a hollow casing fabricated of electrical conducting material with one end closed by an integral end wall and having its opposite end open, a composite closure for said open end consisting of a perforated disc of dielectric material and a parallel contact plate having a central aperture overhanging the perforation of said disc, said closure combining with the end wall of the the casing to define a fluid tight chamber, the contact plate of the closure being insulated by said disc from the casing, a pair of terminals for a normally open circuit, one connected to the casing and the other insulated from the casing and connected to the contact plate, a spring rod attached to the aforesaid end wall and extending longitudinally of the chamber within the casing, a bob weight mounted on said rod having a contact for engagement with the overhanging edge of the aperture of said contact plate to close said normally open circuit upon the flexing of said rod in response to gravity, and scalable means for supplying the chamber of the assembled switch with damping fluid.

8. The combination with a hollow casing, of a pair of terminals for a normally open circuit associated with one end of said casing, one said terminal being electrically connected to said casing, a dielectric member transversely disposed in said casing adjoining said terminals, a thin metallic contact plate secured to one face of said member and insulated thereby from the casing said plate being electrically connected to the other of said terminals, a resilient rod anchored at one end centrally of and electrically connected to that end of said casing opposed to the terminals, a contact carried by said rod to make and break engagement with said contact plate as the rod flexes in response to gravity, and a bob-Weight secured medially to said rod within said casing.

9. The combination with a hollow casing of conductive material closed by a wall at one end and open at its other end, of a pair of terminals for a normally open circuit associated with the open end of said casing, a dielectric member disposed in the open end of said casing adjoining the outer extremity thereof, a relatively thin contact plate secured to a face of said dielectric member and insulated thereby from the casing, one of the aforesaid terminals being electrically connected to said contact member and the other being electrically connected to the casing, a resilient rod anchored at one of its extremities to the end wall of the casing and having its opposite extremity disposed adjoining the contact plate, a bob-veight fixed to said rod medially of its end whereby it flexes in response to gravity, and means whereby the flexing of the rod as aforesaid makes and breaks engagement with said contact plate to close and open the normally open circuit, said means being a continuation of the free end of said red. I

10. The combination with a hollow casing fabricated entirely of electrical conductive material, of a contact plate disposed with its edge spaced from said casing, a dielectric member positioned in contact with the casing and having said plate secured to one of its faces, a pair of terminals for a normally open circuit, one whereof being connected to said casing and the other being electrically connected to said plate and insulated from said casing, a bob-Weight electrically connected to said casing and mounted Within said casing for movement in response to gravity, and means controlled by the movement of said weight to electrically connect and disconnect said terminals by making or breaking engagement with said contact plate.

11. In a gravity responsive switch the combination with a casing closed by a wall at one end and open at its opposite end, of a disc of dielectric material disposed in the open end of the casing in contact therewith, said disc having a central opening and a laterally disposed terminal aperture, a contact plate secured to the inner face of said disc having a contact opening therein in registration with the central opening of the disc and a spring contact finger underlying the lateral terminal opening of the disc, a closure for the open end of the housing electrically connected to the end thereof, a pair of terminals carried by said closure one whereof being insulated therefrom and projecting through the lateral terminal opening of the disc into engagement with the underlying spring finger, and means supported by, and electrically connected to, he end Wall of the housing for movement in the contact opening of said plate to electrically connect the casing and the contact plate and thereby connect said terminals.

References tiited in the tile of this patent UNITED STATES PATENTS 1,345,347 7/20 Chaney 141-7 2,578,024 12/51 Steinmayer 5 3-22 2,618,712 11/52 Moledzky 200-61.51 2,622,163 12/52 Snell ZOO-61.49 2,696,937 12/54 Johnson et a1. 1417 2,705,267 3/55 La Roza ZOO-61.49 2,773,953 12/56 Lawick ZOO-61.51 2,791,653 5/57 Haberland 200-6151 2,850,291 9/58 Ziccardi 2 00-61.51 2,872,495 2/59 Burgess 20061.49 2,874,522 2/59 McCabe 53-22 2,926,223 2/60 Netterfield 200-61.52 2,938,973 5 Swanwick 200--6l.48 2,947,830 8/60 Goss 20061 2,984,820 5/61 Kennell 200-6151 2,997,558 8/61 Shindledecker et al. 200-61.5l 3,073,922 1/63 Miller ZOO-61.48

BERHASLD A. GELHEANY, Primary Examiner.

RICHARD M. jJOOD, MAX L. LEVY, Examiners. 

1. A GRAVITY RESPONSIVE SWITCH COMPRISING A HOLLOW CASING CLOSED AT ONE OF ITS ENDS AND OPEN AT THE OTHER, SAID CLOSED END HAVING SEVERAL INTERNALLY THREADED MOUNTING HOLES EXTENDING PARTIALLY THROUGH IT, A CANTILEVER ROD CENTRALLY AND ELECTRICALLY SECURED TO INNER FACE OF THE CLOSED END OF SAID CASING, AN INSULATING DISC MOUNTED IN THE OPEN END OF THE CASING HAVING A CENTRAL CONTACT OPENING AND A TERMINAL OPENING LATERALLY DISPOSED RELATIVE TO THE CONTACT OPENING BOTH OF SAID OPENINGS PASSING COMPLETELY THROUGH SAID DISC, A CONTACT PLATE SECURED TO THE INNER FACE OF THE INSULATING DISC AND PROVIDED WITH AN OPENING ALIGNED WITH AND SMALLER THAN THE CONTACT OPENING THEREIN, A COVER PLATE OVERLYING THE OUTER-FACE OF THE DISC, PERIPHERALLY CONNECTED ELECTRICALLY TO THE CASING, A PAIR OF TERMINALS CARRIED BY THE COVER PLATE, ONE ELECTRICALLY 